NPDES and some WQM permits require permittees to monitor their treated effluent for specific pollutants or parameters to confirm compliance with effluent limitations, collect information for future assessments, and/or verify operational performance of treatment facilities.
Permits specify the minimum monitoring frequency and sample type for each parameter. For example, most permits for sewage treatment plants require a daily grab sample measurement for pH, Dissolved Oxygen (DO), and, if chlorine is used for disinfection, Total Residual Chlorine (TRC).
In lieu of collecting a sample of effluent daily for these parameters, some plants choose to install a continuous monitoring system that records parameter concentrations multiple times during a day.
While continuous monitoring is not required unless specified in the permit, it is a viable option for plants that wish to have real-time performance data on these key effluent parameters.
If such a system is installed, consider adding an alarm function to warn the owner or operator when concentrations are near or are exceeding effluent limitations.
Below are links to wastewater buyers’ guides that may be used to search for continuous monitoring equipment and other wastewater equipment.
Discharge Monitoring Reports
Wastewater monitoring data required by permits are typically recorded on Discharge Monitoring Reports (DMRs) and DMR Supplemental Reports.
Traditionally these reports have been filed on paper, but DEP’s electronic DMR (eDMR) system is now a frequently used alternative.
DEP encourages anyone involved in the preparation of DMRs to review DEP’s published DMR instructions and guidance:
DEP takes falsification of DMR data seriously and may pursue civil and criminal actions against anyone found to have falsified records submitted to DEP.